It is your crappy psu, no offense to you. It's crappy an can't provide your system enough juice anymore to handle under load situations.
If I was you I'd get rid of it as soon as possible before it fries the rest of your system.
I know I took a big risk doing this. I'll definitely get a more reliable one. Would 400w be enough for my specs?
Whenever I build a computer, I always over compensate on the PSU. PSU's degrade over time losing wattage and you may want to upgrade later on down the road requiring a beefier PSU, saving you money on buying yet another PSU.